Solar Power

[mtrecon]

Just bought a SMB and would like to put a solar system in. Looking for any recommendations, prefer a do it yourself.

[mjeffrey]

A few thoughts below. Feel free to ignore any or all of it It's just what I remember from doing my panel last year - sorry if it's too much!!

- Kyocera seems to be the panel of choice, mainly the KC130 or KD135, I think they are. The 135 is a bit longer than the 130; if you're mounting it transversely, it doesn't leave enough space on a pop-top to mount from the ends. Both give you about 10A under ideal conditions. Arizona Wind and Sun had good prices on these panels last year; I haven't shopped around recently.

- I did see some good deals on panels from Evergreen Solar. Mostly on their blemished panels - but nobody can see your panel on the roof anyway, so cosmetic blemishes don't really count for anything.

- As far as solar controllers, you definitely want MPPT. I think it stands for 'maximum power point tracking' or somesuch; basically, your panel is closer to a 17V power source than a 12V power source when it's really cranking. An MPPT controller can turn the extra voltage into extra amps at 14V or so. Non-MPPT controllers just waste this extra power.

- Blue Sky are the popular controller with Sportsmobiles. I've heard that the Morningstar controllers are even more efficient, but at the time the controller plus the digital readout (which I wanted) was quite a bit more than what I could get a Blue Sky one for. Not sure what the prices are like now. With one panel, I figured the difference in efficiency wouldn't be huge. On the other end of the spectrum, I hear that Xantrex solar controllers are not good (but this is from the crotchety old marine electric man in town, so take it with a grain of salt!).

- Wiring the panels is very simple. Basically, two wires from the panel to the controller, and from there to the battery. That's it. If your panel has the new latching connectors (and you don't want to void your warranty by cutting off the connectors) buy a single extension cable and cut it in half. That way, you'll have two wires, each with a plug and a bare end.

- I bought the temperature sensor for my controller. I can't remember the reasoning behind it now, but at the time, after much research, I decided it was worth it The basic idea, I think, is that a battery will charge more quickly if the voltage is correct for the battery's temperature. Controllers with a temp sensor can adjust based on your battery's temp.

- I mounted my panel with 3M VHB double-sided tape. Hasn't budged, and apparently it's not an uncommon way to mount panels on RVs. It can save a lot of headache in sealing up holes into the top. For the wiring, I put it through the top with a marine "through hull" fitting (from West Marine).

That's all that comes to mind right now. Feel free to ask any questions, and anyone please correct any misinformation I may be spreading above

Cheers,
Mike.

[billwilson]

Great stuff MJeff

To calculate what you need:

What is your goal?

keep starter battery topped up?
run a sterio?
watch TV?

IMHO you need to know what you are gonnna run
calculate watt hours or amp hours
(hunt around the net on how to do, or someone will chirp in)
(many appliances have it stamped on it, they you have to convert watts into amp hours)

then how many amp hours of storage in your battery

then how watts per hours of chosen panel

(i havent had coffe yet, sorry)

My rig's over estimation:
4 hours of lights
3 hours of laptop
4 hours of tv'dvd
charge 2 iPhones
run the 4.2 cu foot fridge 24 hours
(however is is not running all that time, which is another calculation)

What my OVERESTIMATED calcs gave me
Two - 180 watt kyoceras
one blue sky controler
400 amp hours of battery (1-4d and 2 - group 27's)
and 5+ hours of sun
EQUAL = draining battery down to 12v which is ok for the next day

Short version:
figure out what you wanna do
calculate watt hours of panel times sunlight plus amp hour storage

My system is desingnd so i dont have to ever plug in if i have @ 5 hours of sun

A benifit of this:
1) dont have to run the motor or generator
2) the panels double as a helipad

[mtrecon]

This is great information and I appreciate all the help. I have been on other sites before and I am sure the responses I would have received would have been more of a joke than help. Thanks again

[daveb]

Someone posted about flexable panels. I would look closely at these. Glass panels are subject to breaking; one of mine lasted a whole week when the CB antenna flung back and poof....400 buck gone in a flash. Now I worry a bit about things dropping on them. I will say since 2006 I've had some close calls but nothing big has fallen on the van yet. I'm sure even the flex panels can be damaged but most of these type solar arrays are made for the boating industry and are designed to be walked on. Whether I would or not is another situation. You would still want to have them installed on some sort of a rack rather than glued to the roof for air cooling properties but you should contact the manufacture before installation. It might void a warrantee of some type. This also applies to glass panels. Many manufactures will only warrantee specific panels for RV use. If you have Aluminess or another company make some kind of rack you can have the rack designed for off road lighting and roof top storage. If your top is the push up type, weight is gonna have to be factored in.
The main thing is to keep your batteries up (read up on battery care). Hit the archives on this site.
My post about electrical on autoramblings has several good must read links.
Have fun with your new ride.
Dave B

[billwilson]

mtrecon

1) we need pics of your rig

2) what are your power requirements?

3) what is your current total amp hour storage?
(and what type batteries)

4) current charging methods available existing on rig?


with this then, IMHO we can better assist you

bw